500 kV GCB Operation

The gas circuit breaker (GCB) is high performance, large capacity single pressure dead tank gas circuit breaker and is able to be applied to gas insulated switchgear.

Closing Operation.
When a closing command is received, the closing coil (B-210) is energized and catch (B-211) and the latch (B-212)is disengaged, the closing valve (B-240) is opened by force the closing spring (B-256).


















The compressed air pushes the check valve (B-207) to shut off the opening for atmosphere and is fed into the left side of the operating piston (B-301).

The operating piston (B-301) is actuated to the right side and the gas-air lever (B-401) is turned 60 degrees to right side direction and insulating operation rod moves upwards.

The toggle (B-402) maintains the closed positions of the operating mechanism by the retaining spring (B-403).

The compressed air is also fed into the resetting piston (B-276) and actuates the toggle spring mechanism (B-290) to reset the closing valve (B-240) and the latch (B212) to the original positions.

The movement resetting piston (B-276) makes free the movement of cylinder valve with rod (B-261).


















The delay "a" contact (C-403) which is mechanically coupled with the shaft of the toggle lever (B-291) close and then the tripping signal can be received.

The compressed air in the operating piston (B-301) is exhausted from the closing valve and check valve (B-207) to the muffler with silencer (B-500).


















Opening Operation.
When a tripping command is received, the trip coil (B-230) is energized and the magnetic force in the magnet (B-232) is offseted so as to release the armature piece (B-236) by the opening spring (B-237).

The opening lever (B-239) actuates the trip valve (B-260) and the compressed air is fed into the right side of the operating piston (B-301), and the gas-air lever (B-401) is turned 60 degree to left side direction and the insulating operation rod moves downward.

















At the stroke end of the operating piston, the dumping force of the oil dashpot (B-303) is acted upon the driving shaft of operating piston and the mechanical stress is absorbed.

The toggle (B-402) maintains the operating mechanism in the open positions by the retaining spring (B-403).

The compressed air is fed into the resetting piston (B-276) and cylinder valve with rod (B-261) and the armature piece are resetted to the original positions by the opening lever (B-239) movement.

The toggle lever (B-291) makes free the movement of the cylinder valve "close" and makes hold control block in open position securely by means of toggle spring (B-292).

Adopted from Toshiba.